Elastic-plastic stage internal force analysis method for tunnel segment considering the bearing performance of reinforcement

Due to the existing structural internal force calculation methods generally treat the structure as concrete to calculate the internal force, ignoring the impact of reinforcements, resulting in large internal force calculation errors. This study introduces a theoretical calculation method for internal forces in reinforced concrete structures that accounts for the influence of reinforcement. This study reveals the load bearing process of shield tunnel segments, first establishing a theoretical method for internal force analysis in the elastic range, which is then extended to the plastic range using numerical modeling. The analysis reveals that reinforcement strain provides broader applicability compared to concrete strain, which is only valid in the elastic phase but offers component installation advantages. Combined with the in-situ experiments of structural internal force monitoring in Liucun Tunnel, the error between the existing conventional method and the newly proposed method in this research is analyzed, and the practicality of the method was proved. According to the comparison results, it is found that the axial force is underestimated by about 9 % and the bending moment is underestimated by about 13.05 % in the calculation of the internal force of the tunnel without considering the reinforcement.